The long-term objective of this project is to develop a theory of brain function that explains the dynamics of the cerebral cortex in the operations of sensation, perception, conception, memory and other cognitive processes. The long-term result is expected to be a set of procedures, based on a new understanding of the fundamental physical "code" underlying mental process, that would allow precise clinical evaluation of malfunctions of the brain's "information processing" in disorders such as schizophrenia. The specific aims of this project are: (1) to advance understanding of neurocognitive processes by providing more detailed and specific measurements of the spatial and temporal characteristics of neuroelectric neurocognitive signals; and (2) to test and extend theories and analytic methods of mass neural action developed in mammalian paleocortex to the human neocortex. This ill involve measuring detailed spatial patterns of low and high frequency neuroelectric activity related to stimulus, response and cognitive factors of a somatosensory-motor judgment task, including the tie intervals during which these patterns occur, the size and location of their spatial domains, and temporal spectral bands in which the activity is concentrated. We plan to do this first with recordings from subdural electrode grids implanted for diagnostic purposes in patients wit refractory seizures. Then we will extend the analysis to arrays of scalp electrodes, first from the same patients and then from healthy subjects. Substantive progress during the first 2 years of this grant includes: development of a task and methods to record and analyze EEGs from 124- electrode scalp arrays and 60-channel subdural electrode grids; completion of nine 124-channel calibration recordings during finger stimulation and 3 60-channel subdural grid recordings from patients performing the somatosensory discrimination task; development of unique algorithms and software for 3-dimensional compute reconstruction sand modeling of subjects' brains from Magnetic Resonance Images (MRIs); and extensive efforts to disseminate information about our methods and results to other researchers. Preliminary analysis of the subdural data suggests that analytic techniques originally developed for paleocortex will be applicable to the human neocortex. Preliminary analysis of the scalp EEG data and 3-D MRI brain models suggest that great improvements in functional localization from scalp-recorded data are forthcoming. In summary, the various components of the research program are all well underway, and we propose to continue with data collection, algorithm development, signal processing and data analysis. We expect the this project will result in substantial advances in measuring and understanding the mass neural substrate of human cognition.